Plans to station thousands of Western troops in Afghanistan have created a dangerous rift between American and British officials and are threatening to cause a confrontation with the Northern Alliance.

Concern was growing last night over the safety of 120 members of the Royal Marines' Special Boat Service at Bagram air base, near Kabul, and there was no clear indication of when 2,000 paratroops and marines would be sent in to reinforce them.

There was confusion over Britain's attitude to the Northern Alliance. The newly dispatched ambassador to Kabul, Stephen Evans, consulted Abdullah Abdullah, the Alliance's foreign spokesman, over the deployment of more British forces, while Downing Street insisted that objections from the Alliance would not stop the troops going in.

The Northern Alliance was refusing to allow French forces into Afghanistan from Uzbekistan to take over an air base at Mazar-i-Sharif in the north.

At Westminster, the Government's emergency anti-terrorism laws won a massive 453 majority in the Commons despite cross-party criticism of David Blunkett's plans to detain suspects without trial. Labour backbenchers had questioned the speed with which the Home Secretary was pressing through the laws. One of the five who voted against, Brian Sedgemore, said they were "a ragbag of the most coercive measures".

While government sources dismissed allegations of a rift between Tony Blair and President George Bush, there were reports of friction at a lower level. The US State Department was said to be against the idea of large numbers of Western troops being stationed in Afghanistan. Washington's aims appeared to end with the capturing and killing of Osama bin Laden and the removal of the Taliban, defence and diplomatic sources in London said.

They said the Northern Alliance was taking advantage of America's reluctance by saying that the Allies should not send thousands of troops. They have also seized on a UN statement that said the marines at Bag-ram were not part of its humanitarian plans.

A senior military source said: "The State Department appears to be pushing its own agenda in Afghanistan and there is certainly a feeling among both American servicemen and officials on the ground that they do not want to see large numbers of British troops there. There is a feeling among some US personnel that this is a US show and they don't want outside interference. At the same time, our military commanders would much rath-er have Alliance co-operation to deploy in Bagram. [Otherwise] we'll have tremendous difficulty getting supplies in."

Donald Rumsfeld, the US Defence Secretary, said America would not be party to a deal allowing Mullah Mohammed Omar, the Taliban leader, to leave Kandahar, where US bombing continued yesterday.

The 120 British marines at Bagram are surrounded by Northern Alliance troops. But beyond them in the hills are hundreds of Taliban fighters who could seize the opportunity to attack the Western troops while they are stationary.

Mr Evans said after the meeting at Bagram: "Decisions have got to be made. Obviously there will be the closest consultation with our colleagues here in Kabul." But in London, Mr Blair's official spokesman said: "The Prime Minister gave a pretty clear signal of our willingness and readiness to commit further forces ... I doubt you have seen the last of our forces in Afghanistan."

There were reports of a temporary ceasefire at Kunduz, in the north. General Rashid Dostum, an Alliance commander, said a deal had been agreed under which Taliban forces would surrender their arms, although that was later denied by other Alliance leaders.

¿ Barely half the public, or 51 per cent, believes the bombing campaign against Afghanistan is justified, an ICM poll for The Guardian has found. That compares with 29 per cent who said it was not justified. Overall support for military action has risen to 66 per cent since a "wobble" three weeks ago, although it has not returned to the peak of 74 per cent immediately after 11 September.